Tese de Mestrado Integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2012

Tese de doutoramento. Engenharia Química e Biológica. Faculdade de Engenharia. Universidade do Porto. 2008

Orientador: Oswaldo Francisco de Almeida Junior / Banca: Tamara de Souza Brandão Guaraldo / Banca: Sueli Bortolin / Banca: Rovilson José da Silva / Banca: Cláudio Marcondes de Castro Filho / Resumo: Reflete sobre as práticas de leitura realizadas na plataforma digital Skoob. A internet representa uma importante ferramenta de comunicação pautada em interatividade, massividade, compartilhamento e velocidade. Essas potencialidades interativas instituíram uma nova dinâmica entre produtores e consumidores de conteúdos. A hipótese é que esse espaço de socialização de experiências literárias interfere diretamente no consumo e na relação que se estabelece entre o leitor e o livro, revelando novas práticas de leitura. Reflete também sobre a atuação do leitor que ao compartilhar suas impressões de leitura e permitir o monitoramento das suas atividades na plataforma desencadeia ações de mediação, reduzindo a atuação dos filtros tradicionais e interferindo diretamente na produção e no consumo dos artefatos culturais. A pequisa, de cunho qualitativo, recorre ao método Etnográfico, e divide-se em duas partes, análise das Listas dos "Mais Lidos" e dos 'Mais Lendo" e avaliação dos Perfis Leitores. Os resultados apontam que as mudanças mais significativas em relação as práticas de leitura estão associados ao protagonismo do leitor. A atuação do leitor na plataforma é múltipla, ele atua como leitor, mediador e crítico. É preciso considerar que o ciberespaço reconfigura papéis e desestrutura conceitos solidificados. Portanto, consideramos o protagonismo do leitor tende a aproximar o livro dos leitores, além de incentivar e estimular o gosto pela literatura. / Abstract: Reflects on the reading practices performed on the Skoob digital platform. The Internet represents an important communication tool based on interactivity, massiveness, sharing and speed. These interactive potentials have created a new dynamic between content producers and consumers. The hypothesis is that this space of socialization of literary experiences interferes directly in the consumption and the relationship that is established between the reader and the book, revealing new reading practices. It also reflects on the performance of the reader who, by sharing his reading impressions and allowing the monitoring of his activities on the platform, triggers mediation actions, reducing the performance of traditional filters and directly interfering with the production and consumption of cultural artifacts. The qualitative research is based on the Ethnographic method, and is divided into two parts, analysis of the "Most Read" and "More Reading" Lists and evaluation of the Reading Profiles. The results indicate that the most significant changes in reading practices are associated with the protagonism of the reader. The reader's performance on the platform is multiple, he acts as a reader, mediator and critic. One must consider that cyberspace reconfigures roles and deconstructs solidified concepts. Therefore, we consider the protagonism of the reader tends to approximate the book of the readers, besides encouraging and stimulating the taste for literature. / Doutor

No description available.

This paper describes attempts to model the modules of early vision in terms of minimizing energy functions, in particular energy functions allowing discontinuities in the solution. It examines the success of using Hopfield-style analog networks for solving such problems. Finally it discusses the limitations of the energy function approach.

Fractional order calculus (FOC) has wide applications in modeling natural behavior of systems related to different areas of engineering including bioengineering, viscoelasticity, electronics, robotics, control theory and signal processing. This thesis aims at modeling a lossy transmission line using fractional order calculus and identifying its parameters. A lossy transmission line is considered where its behavior is modeled by a fractional order transfer function. A semi-infinite lossy transmission line is presented with its distributed parameters R, L, C and ordinary AC circuit theory is applied to find the partial differential equations. Furthermore, applying boundary conditions and the Laplace transformation a generalized fractional order transfer function of the lossy transmission line is obtained. A finite length lossy transmission line terminated with arbitrary load is also considered and its fractional order transfer function has been derived. Next, the frequency responses of lossy transmission lines from their fractional order transfer functions are also derived. Simulation results are presented to validate the frequency responses. Based on the simulation results it can be concluded that the derived fractional order transmission line model is capable of capturing the phenomenon of a distributed parameter transmission line. The achievement of modeling a highly accurate transmission line requires that a realistic account needs to be taken of its parameters. Therefore, a parameter identification technique to identify the parameters of the fractional order lossy transmission line is introduced. Finally, a few open problems are listed as the future research directions. / Controls

Broadband over Power Line (BPL) technology has garnered significant attention lately due to recent advancements in solid state technologies and channel coding schemes. The successful application of BPL technology for in-home automation and networking has led to suggestions of applying BPL in other systems including ships. The application of BPL technology using the Shipboard Power System (SPS) as a potential communications network for ship automation systems has been proposed, to achieve recent U.S. Navy ship management concepts geared toward reducing ship manning while improving operational efficiency. This thesis presents an analytical model developed to examine the channel response characteristics and estimated throughput capacity of SPS cables. The work used a multiconductor transmission line theory based approach to model the channel response of SPS distribution lines and estimated the channel throughput capacity using a “water-filling” communication technique. This work found that BPL using the SPS holds a strong potential for use as a communications network for ship communication systems.

The current project addresses the productivity improvement of a manual assembly line by making use of operations analysis in the framework of Lean production. A methodology is proposed that helps to improve the productivity of any production process. The methodology consists of selecting a product or product family to be studied followed by current process study. Once the existing process is documented, all the assembly tasks involved must be timed using time study techniques. Operations analysis enables the reduction of non-productive tasks and results in a set of standardized work elements along with the set of standard procedures for performing the operations. Assembly line balancing along with the associated operations analysis assists in constructing or re-configuring an assembly system, which is the key step in improving the overall performance of an assembly line. Following this approach, two manual assembly line configurations (single stage parallel line and five-stage serial line) are constructed for a case study. The results show that by changing over to the single stage assembly line configuration the operator productivity is doubled when compared to the existing assembly method.

With wide adoption of on-line instruction as a new instruction format in higher education in the U.S. and the fast growing population of international students coming to pursue degrees in America, the exploration of international students’ perceived needs and expectations towards this new learning experience becomes critical. Chinese students are the second largest group of international students in the U.S., yet, studies on their learning needs and challenges in on-line learning are limited. This case study aims at exploring the experiences of three Chinese graduate students, who major in education and have taken at least one on-line course in their programs. Data were collected through three in-depth individual interviews with the participants. Three research questions guided the study: 1) How do Chinese students feel about taking an on-line course as compared with traditional face-to-face lecture? 2) How confident do Chinese students feel about their language competency when they participate in the discussions of an on-line course? 3) What is Chinese students’ understanding of the cultural issues as they participate in the discussions of an on-line course? There were four themes generated from the cross-case analysis. The themes were: a) preference of face-to-face courses over on-line courses; b) English language proficiency as a major challenge; c) enjoyment of cross-cultural interaction, and personal growth from the experience. Results revealed that: 1) Participants always have a preference for face-to-face format and regarded face-to-face interaction as an indispensible component; yet, since participants also welcome the adoption of on-line technology, they recommended a combination of two or more instruction methods such as an on-line method with face-to-face method or synchronous on-line chats with asynchronous discussion; 2) Limitation in English language proficiency is constantly a major challenge for participants as international students; 3) Participants enjoyed the cross-cultural communication with peers; and 4) Participants consolidated their knowledge base and developed the awareness of being a culturally responsive teacher.

No description available.